#iChannel0 "https://s2.loli.net/2023/09/10/QozT59R6KsYmb3q.jpg"


highp float random(vec2 co){
    highp float a=12.9898;
    highp float b=78.233;
    highp float c=43758.5453;
    highp float dt=dot(co.xy,vec2(a,b));
    highp float sn=mod(dt,3.14);
    return fract(sin(sn)*c);
}


void mainImage(out vec4 fragColor,in vec2 fragCoord){
    vec2 uv=fragCoord/iResolution.xy;

    float noise = random(uv);

    vec3 col = texture(iChannel0, uv).xyz;
    col += (noise - .5) * .2;

    // fragColor=vec4(uv.x,0.,0.,1.);
    // fragColor=vec4(0.,uv.y,0.,1.);
    fragColor=vec4(col, 1.);
}